A class of neural, intracellular, calcium receptors, the calmodulin-dependent protein kinases, will be studied with biochemical and immunological techniques. Two calmodulin-dependent protein kinases that are highly concentrated in nervious tissue and phosphorylate a specific vesicle-associated protein, will be purified. Their molecular and enzymatic properties will be studied and compared to those of calmodulin-dependent protein kinases that have been studied in other tissues. Methods will be developed to detect and purify additional neural calmodulin-dependent protein kinases. Antibodies will be raised to the purified kinases. The content of the membrane-bound kinases will be determined in sub-cellular fractions of rat brain by a combination of enzymological techniques and radioimmunoassay. The sub-cellular locations of the proteins that are phosphorylated by the kinases will be determined, as well. Fluorescent-labeled antibodies will be used to find the cellular locations of the kinases in sections of fixed rat brain. The information about the neural calcium and calmodulin-dependent protein kinases will be used to plan experiments to determine which of the many calcium-regulated neuronal processes are regulated through calmodulin-dependent protein phosphorylation. Such biochemical information will be useful for understanding the mechanisms underlying short-term changes in synaptic function, which are involved in learning and memory. It may also be useful for understanding the control of synapse formation and elimination during development and during regeneration of neural connections.